Broaching tool



June 6,1950 A. E. RICE BROACHING TOOL Filed May 17, 1946 Patented June 6, 1950 UNITED s TATT'ES PATIENT OFFICE.

1TBR,OACHING;TO L

Albert 1E. Rice; Cleveland, 'Ohio -Application May' 1'7,

Afllaims.

V 1 I Mir-invention; relates in general to" a-broaching stool, and more particularly to "a combination -.br,oaching -,too1 comprisinga broaching element randa, guide -:e1ementfor guiding the broaching eelementr with reference to'the workpiece.

An object of myiinvention is the provision of a broaching element panda 1 guide ielement ;for guidingand holding the broaching element as EitiiSTIllOi/Bd relative to the workpiece.

Another object of my inventionis the provision -11Qf ".a ,broaching element iwhich'need not be cartried :by: a mandre1 "0r :other support during the ebroaching operation.

:Anotherobject of;my invention is the provision :of arsingle-broaching element which is of a,uni- .ta1 y 'rstructure and :which is subjected to the .:entire ,broaching load during thebroaching operation.

Qthercobjects and a-fu11er understanding of :m-y invention may be had by referring to the'fol- -1owingdescription; and claimstaken in combinaittion with theaccompanying drawings, in which:

iE'igure 1-is 1a side elevational view of my com- :bined broaching :tool with the workpiece "and :OthQI associated 1 parts shown .in cross-section;

:Figure 2 is a plan view of the arrangement :shown in Figure'l;

Figure 3 is a-perspective view-of a support plate ;'-for supporting the-workpiece and the'guide ele- Zment during broachingoperation;

z-Figure i is an enlarged perspective view :of the 4 eguide element shown in Figure 1;

Figure'B is an enlarged perspectiveiviewof a modified guide element; a

:Figure 61518111 enlargedpperspective view of a efurtherimodified guide element;

.iEigure :7 iisearside; elevational view of e a modifiedrform of. :a scom'bine-dzbroaching' tool and guide i-element, "the :guide s element, :theworkpiece and other associated. partsbeingcshown-in :section;

iFigure i iis .a "plan view; of,- Figure 7 tFigureB iiszan= enlarged. fragmentarycperspective i-viewzofrzthe guide element-.shown in Figure 7;

iF-igure :10 iis can aenlarged "fragmentary per- :spective LVi W of: aimodifiede guide -1ement;- and aFigure :11 iiS x an senlarged fragmentary "perespective viewofrarfurther"modified: guide element.

:W'ithsreference"toiFigure l OfjthB. drawing; my acombined :breaching =too1 :comprises :a breaching ziement 2i whichtzis adapted :to-bezguidedby ,a eguideceiement @efor ihoiding the bnoaching "eleementiz, hagainst arworkpiece 12:2 during bro aching i operation. The wonigpiecaz Z, maybe, in the, form eofeasleeve or it emaygbe -the hub. of a "wheel adeesignedi to have -,a ke way broaoh therein. ,The

i2 workpiece, is adapted to -rest: on top. of aesi pnort :p1ate-25,-:which in vturn is supported-by za work table 24. Ifhe breaching element; 2| "is pressed downwardly by means of ran-am -23 which, may. be ;5 operated by any source of power. flnactual practice, the ram 23 .and-.thework :table Mamas? e constitute \xanyiwell-known type of press-vwhich is .found-in most workshops .and factories. (The work table .eis iprovided with a, work *clearance 10 v segmental opening (32, through which the-broach- -i-ng .element ---is directed during the tbroaching -operation. The supportplate 2-5 may also the provided with a worklclear-ance segment-a1-.;ep.en- -ing-26 throughewhich the-. broaching element 2| ;;15 isidirectediduring .the-ibroachin operation. The

.-v-top surface of cthe support plate 25 maybe provided with a centering tip 3| at the center thereof :whichserves as-aw, means :to reenter :the guide :element r 2 0 thereupon,v the; guide element having rasmallvcentering conicaleopeninginuthe bottom itherein whichsetshverithe .centeringetipie l. -'I-he guide elemental] .ini-Figure i1 is shown insaneen- ,v larged perspeotivetviemin Eigure and eomprises preferably. a tsolidtpiece ofametaLhaving ,anaan- -.-nu1ar external surface 9,39 ,provided with three vguide grooves- 35,-36,and 31. The=depth Df-%$h8 .guide.groove r-is greater -than thei depth ofathe guide grooves 36 and 31, and the deptheof Qthe guide groove est-{is ,greaten-thamthe depth: of -the i130 guide-ygroove -31. The top 51101 1531011 of the guide element .znpm-ay-be ,provided with; aknurledgrip- ,pingyportion -to;facilitate:thevturning of sthe guide elementwithin theqworkpiece.

.The broaching -e1ement zlrhas a straight-longi- 35 1 tudinal backing-wa1l+21 andfaa'plunalityof cutting teethr28ionuthe iopposite isid-eg-wall. The backing wall ,2! and the {cutting teeth. e 28 define aslow tapertwithzthe smalilower end-2:9 oft-he. broaching elemenkconstituting.theestarting end. The-upper 40 tend-is provided with an'elong-atedshanhMzwhich is ,long enough to extend through T the guide ,grooves in the guide: element.

In operation, the workpiece 2 2 is -.placed Jinan the: supportplate 15, after-Which the@ guide 3ele- A5 ,ment 2-fleiseinserted in the opening :38 ofathe workpiece. in actual practice, the external annular surface 39 of the-gguide element-makes ;a :free butwlosesl-iding fitwiththe-internal annular a surface 38 of the workpiece. sThe groove ,-,35-is x aligned withvthe workpiece'iwherec it is =desiredzto broaehthekeyway, in the workpiece. The groove .35 Lin-combination with theworkpiece defineswa first opening ,to receive -;the starting end- 529 of ethe :broaching element. {The next- .step. in the 5 generation is to icausethe ram 23 to press the element shown in Figure 9.

broaching element 2| downwardly through the groove 35. When all of the teeth 28 have completed the cutting of the keyway slot in the workpiece, the broaching element may thereafter be easily drawn through the cut slot, since the shank section 30 is slightly smaller in cross-section than the combined slot and groove 35. After the broaching element is drawn through the groove 35, the next step is to turn the guide element 20 until the guide groove 36 is brought into alignment with the cut slot, after which the broaching element is again pushed downwardly, cutting a deeper slot in the workpiece. After the second cut is made and the broaching element i removed, the guide element 20 is rotated within the workpiece until the guide groove 37 is brought into alignment with the out slot. The broaching tool then is forced through the groove 37 .for cutting the full depth of the slot or keywa in the workpiece. The depth of the slots in the guide grooves 35, 36 and 31 are progressively decreased so that the opening defined by the slot 35 and the internal annular surface 38 of the workpiece is substantially the same as the openings defined respectively by the guide grooves 36 and 3'! with their respective slot depths cut in the workpiece. The upper end of the guide element 2!) may be provided with indicating arrows 4| and 42, which serve as a guide for an operator and indicates that the guide element 28 is progressively rotated first from the guide groove 35 to the guide groove 35, and then from the guide groove 35 to the guide groove 31.

In Figure 5, I show a modified guide element 46, in that it has but two guide grooves 41 and 48, the guide groove 41 being deeper than the guide groove 48.

In Figure 6, I show a further modified guide element 50, in that it has four guide grooves 5!, 52, 53 and 54 of gradually decreasing depths. The guide element in Figure 5 is preferably made for workpieces having small openings therein to be broached, whereas the guide elements in Figures 4 and 6 are designed for workpieces having larger diameter openings to be broached. In actual practice, the guide elements may vary from of an inch up to 1 /8 inches or larger in diameter.

The guide elements shown in Figures 1, 4, 5 and 6 are designed for broaching keyways in sleeves or hubs having an internal annular surface. In Figures '7 to 11, I show a modified form of my invention for broaching keyways or slots in workpieces having an external annular surface. Thus, in Figure '7, the guide element 60 constitutes an annular body having an internal annular surface provided with three guide grooves 82, 63 and 64. The guide element 50 is adapted to freely and slidably fit over the workpiece 6!, which is in the form of a round annular body. The workpiece Si in the drawing is shown as being shorter than the guide element 63, but in actual practice the workpiece may be of any length, so long as it does not extend out of the guide element too far. The groove 62 is deeper than the grooves 63 and and the groove 53 is deeper than the groove 54. The guide element 80 shown in Figure 7 is the same as the guide The operation for the external guide element 68 in Figure 7 is the same as the operation for the internal guide element as shown in Figure 1, in that the grooves 62, 63 and 64 are progressively used for cutting the slot deeper into the workpiece. The Figure 10 shows a modified guide element 65 having two grooves 66 and 61 therein, the groove 66 being deeper than the groove 61. Figure 11 shows a further modified guide element 63 having guide grooves 69, 10, H and 12 therein, the grooves being of gradually decreasing depth in the order named. The broaching element 2| may be the same both for the internal guide element or the external guide element. It is noted, that the broaching element comprises but a single unitary piece and carries the entire load during the broaching operation, in that it is not carried by a mandrel or other device during the broaching operation. In actual practice, a set of broaching elements and guide elements are provided, whereby the operator has a large selection of tools for accommodating workpieces of various sizes and of various dimensioned keyway slots.

Although I have described m invention with a certain degree of particularity in its preferred form, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

I claim as my invention:

1. A tool for broaching a slot in a work piece having an annular surface, said tool comprising a guide element having an annular surface for fitting against the annular surface of the work piece, said guide element having at least a first guide groove and a second guide groove annularly spaced thereabout, said first guide groove being deeper than said second guide groove, and an elongated tapered broaching element having a longitudinal side provided with cutting teeth and an opposite longitudinal side constituting a backing wall, said backing wall and said cutting teeth defining a taper with the small end thereof constituting the starting end, said starting end fitting into said first guide groove with the cutting teeth facing the work piece for broaching a slot in the work piece as the broaching element passes through the first guide groove, said guide element being turnable relative to the work piece for annularly aligning the second guide groove with the slot cut into the work piece by the broaching element passing through the first guide groove, said starting end fitting into the second guide groove and the said slot with the teeth facing the work piece for broaching the said slot deeper into the work piece as the broaching element passes through the second guide groove.

2. A tool for broaching a slot in a workpiece having an annular surface, said tool comprising a guide element having an annular surface for fitting against the annular surface of the workpiece, said. guide element having at least a first guide groove and a second guide groove annularly spaced thereabout, said first guide groove being deeper than said second guide groove, said first guide groove defining in combination with the workpiece a first opening, and an elongated tapered broaching element having a longitudinal side provided with cutting teeth and an opposite longitudinal side constituting a backing wall, said backing wall and said cutting teeth defining a taper with the small end thereof constituting the starting end, said starting end fitting into said first opening with the cutting teeth facing the workpiece for broaching a slot in the workpiece as the broaching element passes through the first guide groove, said guide element being turnable relative to the workpiece for annularly aligning the second guide groove with the slot cut into the workpiece by the broaching element passing through the first guide groove, said second guide groove defining in combination with said aligned slot a second opening, said starting end fitting into the second opening with the teeth facing the workpiece for broaching the said slot deeper into the workpiece as the broaching element passes through the second guide groove.

3. A tool for broaching a slot in a workpiece having an internal annular surface, said tool comprising a guide element having an external annular surface for fitting against the internal annular surface of the workpiece, said guide element having at least a first guide groove and a second guide groove annularly spaced thereabout, said first guide groove being deeper than said second guide groove, said first guide groove defining in combination with the workpiece a first opening, and an elongated tapered broaching element having a longitudinal side provided with cutting teeth and an opposite longitudinal side constituting a backing wall, said backing wall and said cutting teeth defining a taper with the small end thereof constituting the starting end, said starting end fitting into said first opening with the cutting teeth facing the workpiece for broaching a slot in the workpiece as the broaching element passes through the first guide groove, said guide element being turnable relative to the workpiece for annularly aligning the second guide groove with the slot cut into the workpiece by the broaching element passing through the first guide groove, said second guide groove defining in combination with said aligned slot a second opening, said starting end fitting into the second opening with the teeth facing the workpiece for broaching the said slot deeper into the workpiece as the broaching element passes through the second guide groove.

4. A tool for broaching a slot in a workpiece having an external annular surface, said tool comprising a guide element having an internal an- 6 nular surface for fitting against the external annular surface of the workpiece, said guide element having at least a first guide groove and a second guide groove annularly spaced thereabout, said first guide groove being deeper than said second guide groove, said first guide groove defining in combination with the workpiece a first opening, and an elongated tapered broaching element having a longitudinal side provided with cutting teeth and an opposite longitudinal side constituting a backing wall, said backing wall and said cutting teeth defining a taper with the small end thereof constituting the starting end, said starting end fitting into said first opening with the cutting teeth facing the workpiece for broaching a slot in the workpiece as the broaching element passes through the first guide groove, said guide element being turnable relative to the workpiece for annularly aligning the second guide groove with the slot cut into the workpiece by the broaching element passing through the first guide groove, said second guide groove defining in combination with said aligned slot a second opening, said starting end fitting into the second opening with the teeth facing the workpiece for broaching the said slot deeper into the workpiece as the broaching element passes through the second guide groove.

1 ALBERT E. RICE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,050,901 Sundell Aug. 11, 1936 2,393,646 Markstrum Jan. 29, 1946 FOREIGN PATENTS Number Country Date 23,335 Great Britain Dec. 18, 1913 

